Integratable 3D Printed Terahertz Horn Coupler

Frequencies above 100 GHz are envisaged to provide substantially higher capacity and lower latency in wireless telecommunications. Moving to higher frequencies comes with unique challenges to be addressed, including poor coupling efficiency from free space in and out of planar air-core waveguides. Here, we design, fabricate and demonstrate a 3D printed horn coupler which improves the normalized transmittance of a hybrid photonic crystal waveguide by 20 dB. This work provides a fast, convenient and economical way of customizing couplers for different waveguide ports and could be integrated in terahertz devices.